1. Technical Field
The present invention is directed to a body mount for an automotive vehicle or truck. More particularly, the present invention is directed to a body mount in which the vertical cushioning rate may be independently tuned in relation to the lateral cushioning rate.
2. Discussion
Automotive vehicles, and especially trucks are typically equipped with a body mount disposed between the vehicle body and the vehicle frame. The body mount provides additional cushioning between the vehicle body and frame. The body mount also serves to isolate the transmission of vibration energy and impact energy from the vehicle suspension and frame up through the vehicle body.
A variety of body mounts have been developed for different types of vehicle applications. Most of these body mount designs include an elastomeric member which is captured by a support structure for securing the body mount between the body and frame. The elastomeric member may be formed from a variety of plastic or rubber materials.
One example of a simple compression style body mount is a circular or annular elastomeric member which is secured to one or more metal plates. The durometer of the elastomeric member can be chosen for tailoring the characteristics of the body mount. However, this compression style mount is stiff vertically and soft laterally; including both side to side and fore/aft lateral directions. A particular disadvantage of this simple body mount design is that it does not provide firm lateral support for the vehicle body with respect to the frame. Thus, the vehicle body is not restricted from moving in the side to side and fore/aft directions with respect to the frame. This soft lateral support allows excessive motion laterally with respect to the vehicle frame which results in poor shake control of the vehicle.
An additional disadvantage of this compression style body mount design is that it produces a firm vertical cushioning rate which absorbs less energy and provides a harsher ride. Moreover, this body mount design typically has a vertical to lateral cushioning rate ratio of approximately 3:1 (vertical:lateral), allows only minimal tuning of the vertical rate with respect to the lateral rate, and limited options for designing the vertical rate independently from the lateral rate. Another disadvantage with typical prior art body mount designs is that the lateral cushioning rate is constant about the circumference of the mount. Thus, the side to side vehicle cushioning rate is identical to the fore/aft vehicle cushioning rate. Accordingly, this type of mount provides limited design flexibility to a vehicle ride control engineer in designing the mount for use on a variety of vehicles.
In the design of vehicle suspension systems, it is becoming more common to require the body mount to have a soft vertical cushioning rate for enhancing ride comfort, and a firm lateral (meaning both side to side and fore/aft) cushioning rate for providing increased vehicle stability and control. However, this desired feature typically requires a body mount in which the vertical cushioning rate can be tuned or designed independently from the lateral cushioning rate.
In view of the disadvantages associated with the prior art body mount designs, it is desirable to provide a body mount which has a soft vertical cushioning rate and a firm lateral cushioning rate. It is further desirable to provide a body mount which has a vertical to lateral cushioning rate of 1:2, 1:3 or greater, while still maintaining a soft vertical rate. As an additional feature, it is desirable to provide a body mount which allows the fore/aft lateral rate to be designed to be firmer or softer than the side to side lateral rate (or vice versa). Finally, it is desirable to provide a body mount with a one-way orientation or alignment feature forcing the mount to always be installed in the correct orientation within the vehicle.
The present invention is directed to a body mount for coupling a vehicle body to a vehicle frame. The body mount includes a first member disposed on one side of the frame. The first member includes an elastomeric member having a plurality of pads formed about the periphery of the first member for defining a lateral cushioning rate. The body mount also includes a second member disposed on an opposite side of the frame and operably coupled to the first member. As part of the present invention, the second member functions as a rebound cushion for the body mount. A structural collar may be disposed between the elastomeric member and the plurality of pads. The first member allows a vertical cushioning rate defined by the elastomeric member to be designed and/or tuned independently from the lateral cushioning rate.